For example, a multilayer ceramic capacitor is used in a variety of electronic equipment because of high reliability and low cost thereof. Specifically, the multilayer ceramic capacitor is used in information terminals, home electronics, automobile electronic components, and the like. In these use applications, particularly, in a multilayer ceramic capacitor for use application of in-vehicle use or the like, as compared to a typical multilayer ceramic capacitor, securement up to a higher-temperature region is required in some cases and higher reliability is necessary. It is necessary that the multilayer ceramic capacitor is not broken against a voltage to be applied, that is, has high voltage resistance. Further, since a high AC voltage is applied to a resonant capacitor used in a non-contact power supply resonant circuit or the like, the resonant capacitor is required to have high AC voltage resistance as well as high DC voltage resistance.
Patent document 1 discloses a technology relating to a tungsten bronze type composite oxide exhibiting a high specific permittivity and high specific resistance.
However, in the patent document 1, an alkali metal element is contained as a constituent element of a main component. Since the alkali metal element has high volatility, there is a problem in that handling at the time of manufacturing is prone to be cumbersome, for example, a process of filling an alkali metal element needs to be introduced in processes.
Further, since a lattice defect caused by potassium with high volatility easily occurs in the dielectric composition and thus a conduction electron is easily generated, there is a problem in that high DC voltage resistance is difficult to obtain.
Further, patent document 2 discloses a technology relating to a perovskite type oxide having high DC voltage resistance at 150° C.
However, since the perovskite type oxide has a low specific permittivity in a high-temperature region of 175° C. or higher that is expected to be used hereafter, there is a problem in that a desired capacitance is difficult to obtain.
Further, non-patent document 1 discloses a technology relating to a tungsten bronze type dielectric Ba2MTi2Nb3O15 (M=Bi3+, La3+, Nd3+, Sm3+, Gd3+) with a high specific permittivity and a low dielectric loss. The tungsten bronze type dielectric has a high specific permittivity at room temperature of about 100 to 700 and a favorable value of tan δ at room temperature of 5% or less. In addition, non-patent document 2 discloses a technology relating to a tungsten bronze type dielectric Ba2Sm2Ti4Ta6O30 with a high specific permittivity and a low dielectric loss. The tungsten bronze type dielectric has a high specific permittivity at room temperature of about 120 and a favorable value of tan6 at room temperature of 3% or less.
Further, regarding AC voltage resistance, patent document 3 discloses a technology of improving AC voltage resistance using a dielectric ceramic composition containing a compound represented by a composition formula Bax(Ti1-ySny)O3 and an oxide of Zn. By strictly controlling the composition of the dielectric ceramic composition, a high specific permittivity, a low dielectric loss, and high AC voltage resistance are realized.
However, any of the patent documents and the non-patent documents do not mention dielectric properties, DC voltage resistance, and AC voltage resistance which are secured up to a high-temperature region of 175° C. or higher that is expected to be used hereafter. Further, in the patent document 3, since the invention is based on the assumption of a single-plate capacitor of about 1 mm, there is a problem in that necessary AC voltage resistance is not obtainable in a region in which the thickness of the dielectric layer is 10 μm or less like the multilayer ceramic capacitor. In particular, the magnitude of DC voltage resistance or AC voltage resistance is a property that is essential in a multilayer ceramic capacitor used for in-vehicle use, a non-contact power supply, or the like, and this is increasingly required with high breakdown voltage of an in-vehicle module in recent years.